[PATCH] gas: Fix \+ expansion for .irp and .irpc

[Hans-Peter Nilsson]

> Date: Wed, 15 May 2024 00:04:02 -0700
> From: Fangrui Song <maskray@google.com>

> From: Fangrui Song <maskray@gcc.gnu.org>
> 
> .irp and .irpc receive a null macro_entry.  \+ causes a crash after the
> recent \+ support.  Restore the previous behavior.

This patch (your commit b1d28350499d) caused the gas macro
test again to fail for cris-* e.g. cris-elf.  Please have a
look.  Thanks.

brgds, H-P